Creating your first HTML-based AIR application with the AIR SDK

For a quick, hands-on illustration of how Adobe® AIR® works,
use these instructions to create and package a simple HTML-based
AIR “Hello World” application.

To begin, you must have installed the runtime and set up the
AIR SDK. You will use the AIR Debug Launcher (ADL) and the AIR Developer Tool (ADT)
in this tutorial. ADL and ADT are command-line utility programs
and can be found in the bin directory of the AIR
SDK (see Installing the AIR SDK). This tutorial assumes that you are already
familiar with running programs from the command line and know how
to set up the necessary path environment variables for your operating system.

Note: HTML-based AIR applications can only be developed for the
desktop and the extendedDesktop profiles. The mobile profile is
not supported.

Create the project files

Every HTML-based AIR project must contain the following
two files: an application descriptor file, which specifies the application
metadata, and a top-level HTML page. In addition to these required
files, this project includes a JavaScript code file, AIRAliases.js,
that defines convenient alias variables for the AIR API classes.

Create a directory named HelloWorld to
contain the project files.

Create an XML file, named HelloWorld-app.xml.

Create an HTML file named HelloWorld.html.

Copy AIRAliases.js from the frameworks folder
of the AIR SDK to the project directory.

Create the AIR application descriptor file

To begin building your AIR application, create an XML application
descriptor file with the following structure:

Add the root <application> element,
including the AIR namespace attribute:

<application xmlns="http://ns.adobe.com/air/application/2.7"> The
last segment of the namespace, “2.7”, specifies the version of the
runtime required by the application.

Add the <id> element:

<id>examples.html.HelloWorld</id> The
application ID uniquely identifies your application along with the
publisher ID (which AIR derives from the certificate used to sign
the application package). The application ID is used for installation,
access to the private application file-system storage directory, access
to private encrypted storage, and interapplication communication.

Add the <versionNumber> element:

<versionNumber>0.1</versionNumber> Helps
users to determine which version of your application they are installing.

Note: If
you are using AIR 2, or earlier, you must use the <version> element instead
of the <versionNumber> element.

Add the <filename> element:

<filename>HelloWorld</filename> The
name used for the application executable, install directory, and
other references to the application in the operating system.

Add the <initialWindow> element containing
the following child elements to specify the properties for your
initial application window:

<content>HelloWorld.html</content> Identifies
the root HTML file for AIR to load.

<visible>true</visible> Makes
the window visible immediately.

<width>400</width> Sets
the window width (in pixels).

<height>200</height> Sets
the window height.

Save the file. The completed application descriptor file
should look like the following:

This example only sets a few of the possible application properties.
For the full set of application properties, which allow you to specify
such things as window chrome, window size, transparency, default
installation directory, associated file types, and application icons,
see AIR application descriptor files.

Create the application HTML page

You now need to create a simple HTML page to serve as the
main file for the AIR application.

Open the HelloWorld.html file for editing.
Add the following HTML code:

AIR
defines a property named runtime on the HTML window
object. The runtime property provides access to the built-in AIR
classes, using the fully qualified package name of the class. For
example, to create an AIR File object you could add the following
statement in JavaScript:

Test the application

To run and test the application from the command line,
use the AIR Debug Launcher (ADL) utility. The ADL executable can
be found in the bin directory of the AIR SDK. If
you haven’t already set up the AIR SDK, see Installing the AIR SDK.

Open a command console or shell. Change to the directory
you created for this project.

Run the following command:

adl HelloWorld-app.xml

An
AIR window opens, displaying your application. Also, the console
window displays the message resulting from the air.trace() call.

Create the AIR installation file

When your application runs successfully, you can use the
ADT utility to package the application into an AIR installation
file. An AIR installation file is an archive file that contains
all the application files, which you can distribute to your users.
You must install Adobe AIR before installing a packaged AIR file.

To ensure application security, all AIR installation files must
be digitally signed. For development purposes, you can generate
a basic, self-signed certificate with ADT or another certificate
generation tool. You can also buy a commercial code-signing certificate
from a commercial certificate authority such as VeriSign or Thawte.
When users install a self-signed AIR file, the publisher is displayed
as “unknown” during the installation process. This is because a
self-signed certificate only guarantees that the AIR file has not
been changed since it was created. There is nothing to prevent someone
from self-signing a masquerade AIR file and presenting it as your
application. For publicly released AIR files, a verifiable, commercial
certificate is strongly recommended. For an overview of AIR security issues,
see AIR security (for ActionScript developers)
or AIR security (for HTML developers).

Generate a self-signed certificate and key pair

From the
command prompt, enter the following command (the ADT executable
is located in the bin directory of the AIR SDK):

The HelloWorld.air
argument is the AIR file that ADT produces. HelloWorld-app.xml is
the application descriptor file. The subsequent arguments are the files
used by your application. This example only uses two files, but
you can include any number of files and directories. ADT verifies
that the main content file, HelloWorld.html is included in the package,
but if you forget to include AIRAliases.js, then your application
simply won’t work.

After the AIR package is created, you can
install and run the application by double-clicking the package file.
You can also type the AIR filename as a command in a shell or command
window.

Next Steps

In AIR, HTML and JavaScript code generally behaves the
same as it would in a typical web browser. (In fact, AIR uses the
same WebKit rendering engine used by the Safari web browser.) However,
there are some important differences that you must understand when
you develop HTML applications in AIR. For more information on these
differences, and other important topics, see Programming HTML and JavaScript.

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